A202704 Constructed by the same rule as A185356 and A202690, but with first row 0, 1.

0, 1, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 1, 2, 3, 3, 4, 5, 5, 23, 23, 22, 20, 17, 17, 14, 10, 5, 0, 0, 23, 46, 68, 88, 105, 105, 122, 136, 146, 151, 151, 1141, 1141, 1118, 1072, 1004, 916, 811, 811, 706, 584, 448, 302, 151, 0

Offset: 1

Author

N. J. A. Sloane, Dec 23 2011

Keywords

• nonn
• tabf

Comments

Equals A202690 - A202691.

Examples

			Triangle begins
                   0 1
               0   0 0   1
            1  1   1 1   1   0
         0  1  2   3 3   4   5   5
     23 23 22 20  17 17  14  10  5   0
   0 23 46 68 88 105 105 122 136 146 151 151
		

Links

• M. Josuat-Vergès, J.-C. Novelli and J.-Y. Thibon, The algebraic combinatorics of snakes, arXiv preprint arXiv:1110.5272 [math.CO], 2011.

Crossrefs

Cf. A007836, A185356, A202690, A202691.

Programs

PARI

T(n,k) = {if ((k==0), return(0)); if (n==1, if (abs(k)==1, if (k>0, return(1), return (0)))); if (n%2, if (k<0, sum(j=k+1, n-1, T(n-1,j)), sum(j=k, n-1, T(n-1,j))), if (k<0, sum(j=-n+1, k, T(n-1,j)), sum(j=-n+1, k-1, T(n-1,j))));}
tabf(nn) = {for (n=1, nn, for (k=-n, n, if (k, print1(T(n, k), ", "));); print;);} \\ Michel Marcus, Jun 03 2020

Extensions

More terms from Michel Marcus, Jun 03 2020